Freshwater sponge

Freshwater sponge, any of about 20 species of the genus Spongilla (class Demospongiae, siliceous sponges), a common, widely occurring group. Spongilla species are found in clean lake waters and slow streams.

Freshwater sponge (Spongilla).

Larry West—The National Audubon Society Collection/Photo Researchers

Freshwater sponges are delicate in structure, growing as encrusting or branching masses. They usually appear greenish because of the algae that live on them. Freshwater sponges may attain a volume of more than 2,500 cubic centimetres (150 cubic inches). The larva of the spongillafly lives as a parasite on freshwater sponges.

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in sponge (animal)

any of the primitive multicellular aquatic animals that constitute the phylum Porifera. They number approximately 5,000 described species and inhabit all seas, where they occur attached to surfaces from the intertidal zone to depths of 8,500 metres (29,000 feet) or more. The members of one family,...

Members of the freshwater Spongillidae undergo a slightly different form of gemmulation. Gemmules consist of aggregates of archaeocytes laden with reserve granules; in addition, however, they are surrounded by protective membranes formed by the archaeocytes. The protective covering is generally reinforced by spicules, which vary in shape according to the species and are useful in...

...group of insects (order Neuroptera) that are smoky brown in colour and resemble lacewings. Females deposit clusters of eggs under a silky web near or on the water. The larva lives as a parasite on a freshwater sponge. It leaves the water when fully grown and spins a double-walled, lacelike cocoon in which it passes the pupal stage. Spongillaflies are found throughout the world wherever there are...